• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.7
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• pp.1646-1652
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• 2015

In this paper, we propose a depth conversion method for orthoscopic real image reconstruction in integral imaging. Pseudoscopic image has been regarded a problem in conventional integral imaging. the depth of reconstructed image is depending on a coordinate of an elemental image. The conversion from pseudoscopic to orthoscopic may be possible by analysing the geometrical relation between pickup and reconstruction system of elemental image. The feasibility of the proposed method has been confirmed through preliminary experiments as well as ray optical analysis.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.653-664
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• 2007

Statement of problem: The screw detorque value is a measure of the preload remaining in the screw just before detorquing. Purpose: This study evaluated the effect of different screw tightening sequences and tightening methods on detorque values for a well-fitting implant superstructure. Material and method: An implant superstructure that connected directly to four implants (Astra Tech) was fabricated on a fully edentulous mandibular acrylic resin model. Six well-fitting dental stone casts were made with a pickup impression of the superstructure from the acrylic resin model. To evaluate the effect of three screw tightening sequences (1-2-3-4, 2-4-3-1, and 2-3-1-4) and two tightening methods (2-step and 1-step) on the stability of screw joint, the detorque values for a well-fitting implant superstructure were measured twice after screw tightening using 20 Ncm. Detorque values were analyzed using multi-way analysis of variance and two-way analysis of variance at a .05 level of significance. Results: 1. The mean detorque values for three screw tightening sequences were 12.3 Ncm, 12.6 Ncm, and 12.0 Ncm, respectively. 2. The mean detorque values for two screw tightening methods were 12.0 Ncm, and 12.2 Ncm, respectively. 3. The mean of mimimum detorque values for three screw tightening sequences and for two tightening methods were 10.6 Ncm, 11.1 Ncm, 10.5 Ncm, and 9.8 Ncm, respectively. 4. No statistically significant differences among the variables of screw tightening sequence and tightening method were found (p>.05) for detorque values and for mimimum detorque values. Conclusion: Within the limitations of this study, the screw tightening sequence and tightening method did not have a significant effect on the detorque values for a well-fitting implant superstructure.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.145-154
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• 2004

The growing demand for customer-responsive, made-to-order manufacturing is stimulating the need for improved dynamic decision-making processes in commercial fleet operations. Moreover, the rapid growth of electronic commerce through the internet is also requiring advanced and precise real-time operation of vehicle fleets. Accompanying these demand side developments/pressures, the growing availability of technologies such as AVL(Automatic Vehicle Location) systems and continuous two-way communication devices is driving developments on the supply side. These technologies enable the dispatcher to identify the current location of trucks and to communicate with drivers in real time affording the carrier fleet dispatcher the opportunity to dynamically respond to changes in demand, driver and vehicle availability, as well as traffic network conditions. This research investigates key aspects of real time dynamic routing and scheduling problems in fleet operation particularly in a truckload pickup-and-delivery problem under various settings, in which information of stochastic demands is revealed on a continuous basis, i.e., as the scheduled routes are executed. The most promising solution strategies for dealing with this real-time problem are analyzed and integrated. Furthermore, this research develops. analyzes, and implements hybrid algorithms for solving them, which combine fast local heuristic approach with an optimization-based approach. In addition, various partitioning algorithms being able to deal with large fleet of vehicles are developed based on 'divided & conquer' technique. Simulation experiments are developed and conducted to evaluate the performance of these algorithms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.9
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• pp.1767-1778
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• 2009

A robust and secure InIm(Integral imaging)-based 3D watermarking scheme using cellular automata transform (CAI) is proposed. In the InIm-based 3D watermarking scheme, the elemental image array (EIA) watermark for the target watermark which has to be detected, is synthesized from the computational pickup process of InIm and embedded in a cover image. The EIA watermark can provide a robust reconstruction of the target watermark However, the 3D property of the EIA watermark causes a weakening of the security. To overcome this problem, the proposed method uses the CAT domain to embed and extract the EIA watermark in the cover image. The use of CAT significantly improves the security for our watermarking algorithm using a single secure key only. Experiments are presented to show that the proposed scheme shows robust and secure performances against various attacks.

• The Journal of the Korea Contents Association
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• v.10 no.6
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• pp.1-9
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• 2010

Recently, 3D stereoscopic display such as 3D stereoscopic cinemas and 3D stereoscopic TV is getting a lot of interest. In general, a stereo image can be used in 3D stereoscopic display. In other hands, for 3D auto stereoscopic display, the elemental images should be generated through visualization from every camera in a lens array. Since a lens array consists of several cameras, it takes a lot of time to generate the elemental images with respect to 3D virtual space, specially, if a large bio-medical volume data is in the 3D virtual space, it will take more time. In order to improve the problem, in this paper, we construct an octree for a given bio-medical volume data and then propose a method to generate the elemental images through efficient rendering of the Octree data using GPU. Experimental results show that the proposed method can obtain more improvement comparable than conventional one, but the development of more efficient method is required.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.1
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• pp.32-40
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• 2010

In this work, the method of acquiring the pupil function of optical system is proposed. The wavefront aberration and the intensity distribution of pupil can be analysed with the pupil function. This system can be adopted to the manufacturing line of optical pickup directly and also has good performance to analysing various property of optical instrument. It is one kind of inverse problem to get pupil functions by 3D beam data. The extended Nijboer-Zernike(ENZ) approach recently proposed by Netherlands research group is adopted to accompany to solve these inverse problem. The ENZ approach is one of a aberration retrieval method for which numerous approaches are available. But this approach is new in the sense that it use the highly efficient representation of pupil functions by means of their Zernike coefficients. These coefficients are estimated by using matching procedure in the focal region the theoretical 3D intensity distribution and measured 3D intensity distribution. The algorithm that can be applied more general circumstance such as high-numerical aperture instrument is developed by modifying original ENZ approach. By these scheme, MS windows based GUI program is developed and the good performance is verified with generated 3D beam data.